self.onmessage = async () => {
  let sum = 0
  for (let i = 0; i < 200000; i++) {
    for (let i = 0; i < 10000; i++) {
      sum += Math.random()
    }
  }
  self.postMessage({
    messsage: '计算完成',
    sum,
  })
}
